Which international organization was formed by the US and 11 other countries after WWII?

The formation of the United Nations (UN) took place in 1945, following the end of World War II, with the primary goal of promoting international cooperation, peace, and preventing future conflicts. The United States, along with 50 other countries, established the UN to serve as a global platform for dialogue and to provide a structure for international governance. The UN has become a significant player in global politics, humanitarian efforts, and international law.

The other options represent different organizations formed for various purposes. NATO, formed in 1949, is a military alliance primarily focused on collective defense. The European Union was established much later, with its origins tracing back to the 1950s as an economic union aimed at fostering economic cooperation within Europe. The League of Nations, created after World War I, sought to maintain peace but ultimately failed to prevent the escalation leading to World War II and was succeeded by the United Nations.